Magneto



Dec. 6, 1932. w. E. SCHWARZMAN MAGNETO Filed March 22. 19:50

4 Sheds-Sheet l INVLQNTORV M/4/99407 f: SMko/zmm Y ATToiwEY Dec. 1932- w. E. SCHWARZMAN 1,890,306

IAGNETO Filed larch 22. 1930 4 Sheets-Sheet 2 ATTORNEY Dec. 6, 1932. w. r.-: SCHWARZMAN ,890,306

MAGNETO Q 4 Sheets-Sheet 3 Filed March 22, 1930 IN VEN TOR. Va/F9607 fScn arzm {L/ZQW ATTORNEY 9 w. E. SCHWARZMAN I 1,890,306

MAGNETO Filed March 22. 1930 4 Sheets-Sheet 4 IN VEN TOR.

ATTORNEY throu h I Patented Dec. 6, 1932 UNITED STATES PATENT OFFICE WOLFGANG E. SCHWARZHAN, OI LONGMEADOW, MASSACHUSETTS, ASSIGNOB TO AMERICAN BOSCH HAGNETO CORPORATION, OF SPRINGFIELD, MASSACHUSETTS, A

CORPORATION OF NEW YORK IAGNETO Application fled latch :2, 1930. Serial n.4aa,ou.

This invention relates to improvements in magnetos, and particularly to magnetos for supplying electric ignition current to internal combustion engines.

An object of the invention is to provide an ignition magnetothat is relatively small and compact, of moderate weight, and capable of bein inexpensively produced. It can be easily uilt for engines having a greater or smaller number of cylinders, and the output of the magneto will be large enough for eflicient operation.

A further object of the invention is to provide an i nition magneto of the high tension type, with a distributor mounted in accessible position and adapted to be readily removed when removal is necessary.

Another object of this invention is to provide a magneto suitable for the intended purpose and of inductor design, with rotating magnets, stationary generating windings, and fixed polepieces of especial construction, thus dispensing with a rotatable collector ring and associated parts that are needed in an ordinary magneto with the generating windings located on a movable armature.

Still other objects and advantages will appear from the following description and drawings that disclose a preferred form of the invention, but this description is explanatory only, and one may vary the structure in matters pertaining to shape, size and arrangement of parts, without going beyond the essential principle of the invention, or exceeding the scope of the appended claims.

On the drawings,

Fig. 1 is a vertical, longitudinal section a magneto according to this invention; ig. 2 is an end view thereof seen from the right of Fig. 1; Fig. 3 is a transverse vertical section ta 'en on the line 3-3 of Fig. 1, looking in the direction of the arrows; F1 4 is a transverse vertical section similarly tafien on the line 4 4 of Fig. 1, the rotor magnets being omitted; Fl". 5 is a lon itudinal section of the rotar member of the istributor of the magneto; ig. 6 is a section through the stationary member of the distributor of the magneto on the line 6-6 of Figs. 1 and 8; Fig. 7 is a front view of said stationary member;

Fig. 8 is a top view of. said stationary member partly in section; Fig. 9 is a section through the rotor of the magneto taken partly on the line 9-9 of Fig. 1; Fig. 10 is a top view showing one-half of the framework or body of the magneto; and Fig. 11 is a vertical sectional view of such framework taken on the line 11-11 of Fig. 4.

On the drawings the same numerals identify the same parts throughout.

The magneto comprises a number of parts which are supported in operative relation by means of the body or framework 1, that may be produced as by casting out of any suitable non-magnetic material. The generator windings are shown at 2 mounted above the body or housing 1, and within the housing is a rotatable member or vrotor 3 which comprises ma nets to coact with the stator windings: 2. hese windings may comprise a primary coil and a secondary coil, the circuit of the former being periodically opened by the interrupter of the magneto indicated at 4; and the output of the secondary is su plied to the igniters of the engine through t e terminals of a distributor 5 adjacent to the windin s2.

The ousing or framework 1 comprises a base 6 and sides 7 one end of the housing being closed as indicated at 8, except for an opening for one of the journals or trunnions which supports the rotor 3, and the other end ofthe housing being open. The housing also is provided with top 9 adjacent to the closed end 8. This top extends only part of the distance from the closed end toward the open end of the framework 1.

The top 9 has a transverse aperture 10 for the stator polepieces 11 which are embedded in the sides 7 of the housing and project through the top to enga e the opposite ends of the magnetic core 12 o the stator windings 2. The polepieces 11 and core 12 are of course laminated as shown and so are the polepieces 13 of the rotor 3. The laminations of the polepieces 13 are each perforated to receive the extremities of ermanent magnets 14, which are preferably our in number, two of like larity for each polepiece 13, the latter being in position to cooperate with the ha e1 g in Fig. 1; w thie lis engaging head of magnetic material, and this disc islocated at the open end of thehousing 1. Adjacent to the opposite end is a disc 16 of non-magnetic material and the discs or plates 15' and 16 are rigid with journals or trunnions 17 and 18 respectivel upon which the rotor 3 can be revolved.- T e two discs 15 and 16 are united by tie rods 19 of non-magnetic material and these rods may either have short screws 20 passing through counterbored holes in discs 15 and 16 into threaded holes in the ends of the rods, or the ends of the rods may be reduced and riveted in the holes of discs'15 and 16 so as to bind the parts of the rotor securely together.

The numeral 21 indicates a plate or disc of non-magnetic material against the rotor pole pieces 13, on the side awa from the disc 16, with recesses 22 in its e ge for the tie rods 19, and the ends of the magnets 14,

tized cylindrical steel bars, ma be reduced as indicated at 23 to form annu ar shoulders a inst which the disc 15 and plate 21 are amped by the rods 19. The laminations of the pole ieces 13 have openings of the same size as t e reduced ends of the magnets, and the le ends of the magnets 14 as throu h the aminations as indicated in ig. 1. e polepieces 13 are therefore between the discs 16 and 21, and the ends 23 of the magnets in the polepieces 13 may either pass through opemngs in the disc 16,'or the disc may be without such openings with said ends 23 sim ly abutting said disc.

' e end laminations of the polepieces 11 are of greater length than the intermediate laminations of these polepieces, as indicated in Figs. 1 and 11, and the tops of the polepieces 11 thus form a yoke or seat for the ends of the core 12. Rings or frames 25, which are shown in Figs. 4, 10 and 11, engage the opposite sides of the polepieces 11 within the housing 1, and these rings with the laminations of the two polepieces 11 are bound in a single unit by rivets 26 which also hold the core 12.

The angular extent of the polepieces 13 and the pole faces of the polepieces 11 are" such that when the rotor 3 revolves, the magnetic flux of the magnets 14 is reversed twice for each .revolution, through the core 12. Thus for each revolution of the rotor two impulses of maximum current are developed. The timer or interrupter 4' is at one end of the magneto and the windings 2 are adjacent to the same end. The distributor5is located ad-- jaeentto the o posi'te end of the magneto over the part the housing which is open at the top and this open portion of the top of the'ho I; 1 may be bridged by a cover late 27 of ating material e ape which have the form of permanently magneshouldered seats at the upper parts and along 1 the inner edges of the $1 The fixed part of the distributor comprises a curved member of insulation 28, with upward rojecting flanges 29 at its front and rear aces and between these flanges is a groove 30. From the inner or concave face of the member 28 project contact pieces 31 all lying in the same transverseplane adjacent t e mner or rear face and a complementary number of contact pieces 32 in a different transverse plane adjacent the front or outer face. These pieces 31 and 32 are engaged by means of screws 33 which can be put in lace and removed through bores 34, the hores 34 for the contact pieces 31 openin through the front face of the member 28 an the bores 34 for the members 32 opening throu h the other or rear face of this member.

In ig. 8 the member 28 is shown in such position that the up r side thereof will be the forward face w en this member is put in its proper place on the magneto. Adjacent to each 0 the contact pieces 31 and 32 is a bore 35 which opens through the convex exterior of the member 28 to receive the ends of conductors leading to the sparkplugs of the to receive the terminal 39 attached to one extremity of the wire 40 of the secondary coil of the windings 2. A spring presed plug in the socket 38 ensures electrical connection between the inset 37' and wire 40.

Connected at their inner ends with the inset 37 are bent metallic rods 41 and 42 serving as distributing brushes, the end of the brush 41 projecting through the outside surface of the'rotor 36 in the plane of the contacts 31 and the end of the brush 42 projecting through the head 3 6at a diametrically opjfillsite point in the plane of the pieces 32.

e inset or plug. 37 is in line with a central boss 43 on the head 36 and surrounding this boss is an annular contact or ring 44 at the bottom of a groove 45 in the end of the rotor 36.- Attached to this ring 44 and embedded in the rotor 36 are two other rotating brushes 46 and 47, diametrically opposite each other and projecting through the outside of the head 36 in the transverse planes of the contact pieces 42 and 41 respectively. As shown in Fig. 3 the contact pieces 31 and 32 are five in number so that the magneto is designed to serve for ignition in connection with a 5-cylinder en e. There are three contacts 31 arranged apart and the contacts 32 are likewise 7 2 apart but are located midway of 'the adjacent contacts 31. Also the brushes 46 member 36 as if revolved a bit to carry the brusles 41 and 42 out of the occupy in Fig. 1.,

The rotor 36 has a projecting flange 48 at its outer end which is secured to gear wheel 49 and has portions to receive fastening devices or the like 50. This gear wheel mesheswith a smaller gear wheel 51 rigid with the trunnion 17 and disc 15 and at 52 is a cover or end plate which closes the open end of the housing 1 and shields the distributor 5. The gear 49 has a hub 53 and is mouted upon a ournal 54 made integral with a plate or flange 55 secured to the inside of the cover plate 52. Between the hub 53 and the journal 54 is a ballbearing and the inner end of the journal 54 bears alocking device or nut 57 which holds position they the race-way members of the ball-bearing in place. To make the construction compact the adjacent end of the rotary member 36 is hollowed out to provide a large recess 58 into which the hub 53 and some of the adjacent parts may project. The inside of cover plate 52 may be provided with a circular rib 59 which receives a similar ball-bearing 56' for the trunnion or shaft 17 and the aperture in the closed end 8 of the housing 1 may be counterbored for a ball-bearing 56 surrounding the trunnion or shaft 18. At the top of the cover plate 52 is an openin which may be closed by removable screw p ug 60. Projecting from the front face of the member 28 is a curved rib 61 and the adjacent edge of the concave cover plate 52 is provided with an interior annular shoulder which fits the This cover plate may be secured by means of nuts engaging threaded bolts 63 and 64, projecting from the opposite sides of the base 6 and the ends of the sides 7, the cover having openings through which these shanks extend, and the outer ends of these bolts may receive lock nuts.

The rear face of the stator member 28 also has a curved rib or projection 61 to engage a shoulder within the rim of aconcave cover 65 for the opposite end of the magneto above the housing 1. a

The sides 7 have outturned horizontal projections 66 with openings 67 and the cover 65 will have at its opposite lower edges similar rojections with openings through which can be passed locking bolts 68 to project through the openings 66 and receive nuts to make the cover 65 fast. At opposite sides the cover 65 will have projections 69 to be fitted against projections 7 O on the member 28 and through the projections 69 may be passed blnding screws 71 to enter threaded openings in the projections of the stationary member 28,

thus securing the parts 65 and 28 directly together. Member 28 is thus firmly afiixed between the two cover plates 52 and 65 and cannot be removed unless one or the other of these cover plates is taken off.

The recess in the closed end of the housing 1 for the ball-bearing 56 is shown at 72. Beyond this end of the housing is a tubular extension 73 having lining rings 74 and 75. The casing for the timer is shown at 76. It has a tubular projection 77 of reduced diameter to fit into the extension 73, this projectionbeing secured to the outer face of the bottom of this casing, and surrounded by an annular shoulder 78 which abuts against the outer end of the extension 73. The bottom 79 of the casing 76 is apertured to admit the trunnion 18, which is reduced and shouldered within the casing 76 to carry thereon a cam 80. At 81 is a fixed contact adjustably secured to a support 82mounted in the bottom of the cas ing 76 and insulated therefrom. This contact cooperates with the breaker lever 83. The pivot or'journal 84 for this lever is secured to the bottom 79 of the casing 76 and a spring 85 is attached to this lever and bent around the end thereof as shown in Fig. 2 to force the lever normally into engagement with the contact 81. The journal 84 carries a sleeve or bushing 86 and at 87 is a spring ivotally secured at one end to the bottom 9 of the casing 76 and pressing at its other end upon the journal 84 so that the breaker lever cannot move off this pivot. \Vithin the journal are lubricating passage ducts 88. The bottom 79 of the casing 76 also carries a projection .89 to which the other end of the spring is secured and the lever 83 may have a fibre insert 90 to be engaged by the cam 80. The lever can be taken off any time simply by swinging the spring 87 to one side. The inner end of the support 82 passes through .the bottom 79 and terminates in a binding post 91 for connection with one terminal of the primary coil of the windings 2.

Encircling the casing 76 is a timer ring 92 having an operating arm 93, and this ring may'have toothed engagement with the outside of the casing 76 so that it may be adjustably connected therewith as shown at 94. At 95 is a cover for the casing 76 and at 96 is a clamp for this cover pivoted to a post 97, so that it can be swung into and out of clamping position.

The cover 65 has a recess or pocket 97 on its interior to receive a condenser 98. This condenser may be disposed within a suitable container having a stem 99 projecting through to the outside of the cover 65 and threaded to receive a binding nut to hold the condenser in place. On the condenser is a contact plate 100 and oneterminal of the primarywinding may be attached to this plate 100'by conductor 101, the plate 100 the late 100 may be attached to this core by con uctor lead 107. The other terminal of the primary is grounded in the usual way.

The circuit of the primary is completed through the breaker lever 83 and is broken whenever the cam 80 actuates the lever 83.

The cap 105 of the grounding terminal may be connected to ground in any suitable manner.

In operation when the trunnion 17 is connected to a suitable driving shaft and the rotor 3 revolved, the lever 83 will be actuated twice per revolution by the noses marked on the cam 80. Whenever the lever 83 is actuated the primary windings on the coil 2 are energized, and the primary winding thereof causes the secondary to generate a high voltage which is delivered to the brushes 41 and 42. Su pose at this time the brush 41 is in line wit the contact piece 31 at the left of Fig. 3. In this position high tension current will be delivered to the engine whose sparkplug is connected with that contact piece. After another half revolution of the rotor 3, the timer lever will again be actuated and the same brush 41 will deliver high tension current to the next contact piece 31. After passing the third contactpiece- 31 the brush 41 will be replaced in action by the brush 42 which will deliver current tov the contact pieces 31 in succession. The other brush 41 will then come into action again and the cycle will be repeated. The diameter of the gear 49 is 2% times that of the gear 51 to give this result. I

The cover also carries a booster terminal consisting of an insulating sleeve 108 in a suitable opening in the plate 65. This sleeve has a metallic plug or core 109 at its inner end and to this plug 109 is aflixeda stationary brush 110 which cooperates with the contact ring 44. The core 109 is hollow to receive a projection 111 on a screw plug 112 which screws intdthe open outer end of the sleeve 108. This booster terminal permits current from an outside source to be used to actuate the distributor 5 and this external high tension current is suppl ed to the contact pieces at 31 and 32 by the brushes 46 and 47 in the same manner as. the brushes 141 and 42. Each of the portions 46- and 47 is 72 from the nearestbrush 41 or 42, with the rotation of the member 36 taken as clockwise in Fig. 3, that is to say, the brushes 46 and 47 are arranged to follow the brushes 41 and 42,

so that when the booster is used the ignition is retarded. At this time the noses B on the cam operate the breaker lever in synchronism with the action of the brushes 46 and 47. The booster terminal can be used for starting, or in the event of a mishap which puts the ma eto out of commission.

The insulating plate 27 shields the rotor and prevents sparks jumping from the brushes 41, 42, 46 and 47 to the rotor when the ends of these brushes pass through their lowermost positions. r

The magneto can easily be assembled or taken apart and access to the distributor can be had by removing the front and back plates 52 and 65 or either of these. Ins tion of the timer is afforded simply-by taking off the cap 95 and the whole timer casing 76, and other-parts can be dismounted by withdrawing the projection 77 from the extension 73.

As shown, the rings 25 are approximately square in shape but t e opening at the middle is substantially circular to correspond with the path of, the rotation of the outer curved faces of the polepieces 13. One face of the plate 27 is also concave on the same curvature and the ends of the sideof this plate project as shown at 113 to rest upon the shouldered seats 114 along inner edges of the tops of the sides 7 at their tops. This plate is clamped in place by the distributor 28, but it may be secured .by screwsengaging the seats 114 if desired. The angular extent of the curved polar faces of the polepieces 11 is indicated particularly in Fig. 4.

Whenever the source connected with the booster terminal is used with distributor brushes 46 and 47 for starting the engine or under other conditions, the ring 92 and casing 76 are set to give ignition at the point required, to compensate for the fact that the cam noses B follow the noses A, and the brushes 46 and 47 follow the brushes 41 and 42. When properly manipulated, the arm 93 gives the necessary adjustment of the timer casing 76 and fixed contact 81 at all times for both the booster and the outside source of current, and the magneto.

The insulation for the support 82 where it is mounted in the bottom 79 of the casing 76 is shown in Fig.1 at 115.

The ground terminal and the booster terminal may be secured by bolts 116 and nuts 117. The bushings of insulation may have flanges 118, which will be so shaped as to be elongated, so as to provide oppositely disposed perforated ends to receive the bolts 116.

The breaker lever 83 may have a small.

cushion 119 attached to the side away from the cam 80, to engage a projection 120 on the part 89 secured to the bottom 7 9 of the casing 76, having the spring 83 afiixed thereto, so that the cushion 119 may strike the micetion 120 as the lever 83 is actuated by t a cam to thereby hasten the closing movement of the lever at high speed.

At 121 is a recess in the projection 77 on the casing 76 of the timer or interrupter and in the end 8 is a screw 122 within the extension 7 3 to be received in this recess, so that the casing 76 cannot rotate beyond fixed limits in the extension 73.

Gear 51 011 the shaft 17 may be made rigid with the disc 14 by studs 123 entering apertures in the gear so that the gear 51 will revolve with the shaft 17 and rotor 3;

Having thus described my invention, what I claim is:

1. A magneto having a housing containing a rotor, a enerating coil mounted on the housing, a distributor member on the housing adjacent said coil, and an insulating plate between said mechanism and said rotor.

2. A magneto having a housing containing a rotor, a generating coil, distributor mechanism adjacent the coil and rotor, and an insulation plate carried by housing between the rotor and said mechanism.

3. A magneto comprisin a housing containing a rotor, a coil on t e housing to be energized by the rotor, a cover for said coil, a second cover spaced from the first cover, distributor mechanism between said covers adjacent to and connected with said coil, and

an insulating plate between said mechanism and said rotor. I

4. A ma neto comprising a housing, a gencrating 0011 on the housing, a rotor in the housing to energizethe 0011, a distributor mechanism adjacent to the coil and rotor,

an insulating plate between said mechanism and said rotor, an end plate for the magneto covering one side ofsaid distributor A mechanism, and a cover plate for the coil at the opposite side of said distributor mechanism.

5. A magneto comprising a housing, with sides and a top havlng a closed portion, a rotor having polepieces in the housing, a generating coil, polepiecesat the ends of said coil embedded in the sides of the housing and projecting through the closed portion of the top, distributor mechanism adjacent to the coil and rotor, and an insulating plate over the open portion of the top of said housing between the rotor and the distributing I mechanism.

ported at one end of the housing, a cover plate above the timer for said coil, and a cover plate for the opposite end of the magneto, the distributor member being engaged by both cover plates and projecting between them.

8. A magneto comprising a generating coil and a distributor, the distributor'including a rotary member havin brushes at diametrically opposite points t ereon, but in diflerent transverse planes, and a stationar mem her and contact pieces carried by sai member and spaced angularly a art, said contact pieces being disposed in di erent planes extending transversely of the magneto.

9. A magneto comprising a rotor, a generating coil and a distributor includin a member to be revolved, said member having a plurality of pairs of brushes, one pair of said brushes being connected to said coil, one pair of said brushes being angularly separated from the brushes of the other pair and the brushes of each in dilferent planes extending transversely of the axis of rotation of said member.

- 10.. A magneto comprising a housing with a rotor therein, a generating coil on the housing and a distributor covered on both faces adjacent said coil, said distributor comprising a stationary member having fixed contact pieces and a rotating member carrying brushes to cooperate with part of said contact pieces, said brushes being connected to said coil, an insulated terminal on the magneto to which the remainin brushes are connected, and said contact pieces lying in dif ferent transverse planes, one or more of the brushes being arranged to revolve in each of said planes.

11. A magneto comprising a rotor and a generating coil, a distributor covered on both faces including a stationary member having fixed contact pieces and a rotating member with brushes part of which are connected to the coil, an insulated terminal on the magneto to which the remaining brushes are connected, said contact pieces being located in separate planes transverse to the axis of said rotating member, and said brushes being arranged so that some ofthe brushes cooperate with some of said contact pieces and the remaining brushes with the remainder of said contact pieces.

12. A magneto having a housin with a rotor therein, a generating coil on t e housin g, a distributor member on the housing, said distributor including fixed contact pieces, a

air being located rotary member, and brushes carried by said rotary member, part of the brushes being connected to said coil, an insulated terminal on the magneto to which the remaining brushes are connected, part of said brushes and contact pieces being disposed to eflect I delayed sparking.

13. A magneto comprising a housing with a rotor therein, a generating coil, a distributor comprisin a stationary member with fixed contact pieces, a rotary member, means carried by the rotary member to conduct current from the coil. to part of said pieces in succession, and additional means carried by said rotary member with connections to an current to said contact pieces, an annular contact on said rotary member, a terminal having a brush to cooperate with said annular contact, and brushes connected to said annular contact for conducting current to said contact pieces.

15. A magneto havin a housing containing a rotor, a coil on e housing, a cover for, the coil, said cover containing a pocket,

a condenser mounted in said pocket, an insumake connection with conductors leading to I the coil, the terminal on the cover and the lated'terminal on said cover, a timer casing on the housing, and a conducting plate in said pocket mounted on said condenser to timer. F

16. A magneto comprising a housing, a cm], a rotor for the coil, a distributor adjacent to the coil, the distributor including a member to be revolved, brushes carried by said member, a ring to which said brushes are connected, a cover for the coil, a terminal on the cover, and a brush carried by the terminal to cooperate with said ring.

17. A magneto having generating means and distributing members, one of said members being1 rotary and having two pairs of brushes t e brushes of each pair being diametrically opposite each other and the brushes of one air being an tributor also including a stationary member with fixed contact pieces to cooperate with said brushes.

18. A magneto comprising generatin means and a distributor including a fixe member bearing contact pieces, said fixed member having bores to receive binding screws to engage said contact pieces and additional bores in position to receive the said screws for the attachment of high tension conductors to said member, and a cover for the distributor overlying the ends of said last named bores.

19. The magneto according to claim 18, wherein the first named bores open through one face and the others through another face of said member.

20. A magneto having a housing with a generating coil, one end of said housing havmg an extension and a timer casing having arly separatedfrom the brus es of the ot er pair, the disa projection to be received within said extension and be mounted on said housing, said casing being toothed on its exterior,-with a toothed ring engaging it,-said ring bearing an arm to adjust the casing.

21. A magneto having a rotor and a distributor, the latter comprising a stationary arcshaped member supported at opposite sides of the ma eto, with contact pieces pro-- jecting from its inner face, and a rotary member carrying brushes within the stationary member to cooperate with. said contact pieces.

22. The magneto according to claim 21, with the stationary member bearing contact pieces projecting in a double row. from its inner face, the pieces of one row being staggered with respect to those of the other row.

23. A magneto comprising a rotor, a coil,

a distributor member, a cover plate for the coil, and a cover plate for one side of the distributor member, the latter projecting uncovered between said cover plates.

24. A magneto comprising a rotor, a coil, a distributor member adjacent the coil, a. cov-- er plate for one face of said member, and a cover plate for said coil, the latter cover plate engagmg the opposite face of said member, whic rojects uncovered between said plates.

25. K magneto comprising a rotor, a coil, a distributor comprising a rotary member carrying brushes which are connected to said coil, and a curved stationary member in transverse position enveloping said rotary member, said curved member having contact pieces projecting from its inner face in the plane of revolution of the other member.

26. A magneto comprising a rotor, a gen erating coil and a distributor, said distributor comprising a stationary member having fixed contact pieces, a rotating member carrying brushes to cooperate with said contact pieces, part of said brushes being connected to the coil, an insulated terminal on the magneto connected to the remainder of said brushes, said contact pieces and said brushes being so arranged that each brush operates exclusively with part of said contact pieces.

27. A magneto comprising'a rotor and a generating coil, and a distributor including a stationary member bearing fixed contact pieces and a rotating member with brushes part of which are connected to the coil, an insulated terminal on the magneto connected to the remainder of said brushes, said contacts being located in separate planes transverse to the axis of said rotating member, said brushes being arranged so that each operates exclusively with the contact pieces in one of said planes.

In testimony whereof I afiix my signature.

WOLFGANG E. SCHWARZMA'N. 

